(CNN) -- Thirteen cases of infection with E. coli bacteria may be linked to a multistate beef recall, the beef producer and Arizona state health officials told CNN Thursday.

No deaths have been reported in connection with the recall, but four people are hospitalized, according to United Food Group, which greatly expanded the recall on Wednesday.

UFG says illnesses were reported in five states -- three in California, four in Arizona, two in Colorado, one in Wyoming, and one in Utah.

However, Michael Murphy, spokesman for Arizona Department of Health Services said that health officials had identified six cases in that state and, "in at least two, we definitely tied them to eating ground beef," he said.

The beef linked to those two cases is a few days outside the recall dates announced by United Food Group, but test results indicate it was contaminated with E. coli, Murphy said. UFG "may want to consider expanding the recall dates," he said.

Two of those infected in Arizona were hospitalized but recovered, and an investigation into the other cases continues, Murphy said.

The company announced Wednesday that it had expanded the recall of its ground beef products sold in 11 states to nearly five times the original amount.

On Sunday, the recall covered 75,000 pounds of beef. The recall was expanded on Wednesday to include 445,000 pounds of beef suspected of being contaminated with E. coli bacteria.

People who eat E. coli-contaminated food typically exhibit symptoms such as severe bloody diarrhea and stomach cramps within eight days of exposure, according to the Centers for Disease Control and Prevention.

In some people, particularly the elderly and children under the age of 5, the bacteria can cause kidney failure and death, the CDC said.

The recall was expanded "because the company's policy is to err on the side of caution in its effort to protect public safety," and "based on concerns raised by the California Department of Health Services," UFG said in a statement.

The meat was produced in Vernon, California, on April 13 and sold under the brand names of Moran's All Natural, Miller Meat Company, Stater Bros., Inter-American Products Inc., and Basha's, with sell-by dates from April 20 to May 7.

Stores in 11 states -- Arizona, California, Colorado, Idaho, Nevada, New Mexico, Oregon, Utah, Washington, Wyoming and Montana -- sold the product, according to UFG.

Sam's Clubs in California, Arizona and Nevada were the only stores belonging to that chain stocked with the recalled product.

The voluntary recall was announced in cooperation with U.S. Department of Agriculture and the California State Department of Health Services, the company said.